Advancements in information technology have simplified peoples' everyday lives and led to the popularization of tablet computers, smart phones, and laptops. Such electronic products are built-in with peripheral devices, such as touchscreen display, keyboard, and touch panel, for users to enter instructions. These peripheral devices are generally modularized to facilitate assembly and disassembly and utilize flexible circuit boards to electrically connect to connectors within the electronic products, so that data signals input by the users from the peripheral devices are transmitted by the flexible circuit boards to the electronic products.
Referring to FIGS. 1 and 2. FIG. 1 illustrates a perspective view of a peripheral device according to the prior art, and FIG. 2 illustrates bending of the peripheral device of FIG. 1 when an external force is applied. As shown in FIGS. 1 and 2, circuit board 30 of peripheral device 10 includes a flexible extension 34, and baseplate 20 for carrying the circuit board 30 includes a edge 20a. Side 34a of the flexible extension 34 is perpendicular to the edge 20a of the baseplate 20. When the flexible extension 34 of the circuit board 30 is bent and stretched by an external force, stress would be concentrated at the intersection between side 34a of the flexible extension 34 and edge 20a of the baseplate 20, causing the sharp edge 20a to cut and damage the flexible extension 34, break the internal wiring of the circuit board 30, and therefore malfunction in electrical conduction or signal transmission of the peripheral device 10.